In the 3rd Generation Partnership Project (3GPP), a radio access method and a radio network for cellular mobile communications (hereinafter referred to as “Long Term Evolution (LTE)” or “Evolved Universal Terrestrial Radio Access (EUTRA)”, and a radio access method and a radio network for achieving data communications with higher speed by using a wider frequency range (hereinafter referred to as “Long Term Evolution-Advanced (LTE-A), or, “Advanced Evolved Universal Terrestrial Radio Access (A-EUTRA)”) have been studied (see NPL 1 and NPL 2). In LTE and LTE-A, a base station apparatus is also referred to as an evolved NodeB (eNodeB), and a terminal apparatus is also referred to as a User Equipment (UE). LTE and LTE-A are cellular communication systems in which an area is divided into multiple cells to form a cellular pattern, each of the cells being served by a base station apparatus. In some situation, a single base station apparatus manages multiple cells.
In LTE-A, a base station apparatus schedules assignment of a radio resource such as the frequency band and the transmission power for a terminal apparatus. The minimum assignment unit of a radio resource is called Resource block (RB). A single RB includes 12 subcarriers in the frequency direction, and seven or six symbols in the time direction. The minimum time unit of scheduling is a subframe, and is also referred to as Transmission Timing Interval (TTI).
In 3GPP, use of a shorten TTI (sTTI), which is shorter than a TTI, is studied in order to reduce packet delay (see NPL 1 and NPL 2).